x86: PAT infrastructure patch
Sets up pat_init() infrastructure.
PAT MSR has following setting.
PAT
|PCD
||PWT
|||
000 WB _PAGE_CACHE_WB
001 WC _PAGE_CACHE_WC
010 UC- _PAGE_CACHE_UC_MINUS
011 UC _PAGE_CACHE_UC
We are effectively changing WT from boot time setting to WC.
UC_MINUS is used to provide backward compatibility to existing /dev/mem
users(X).
reserve_memtype and free_memtype are new interfaces for maintaining alias-free
mapping. It is currently implemented in a simple way with a linked list and
not optimized. reserve and free tracks the effective memory type, as a result
of PAT and MTRR setting rather than what is actually requested in PAT.
pat_init piggy backs on mtrr_init as the rules for setting both pat and mtrr
are same.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/cpufeature.h b/include/asm-x86/cpufeature.h
index 90feb6f..0d609c8 100644
--- a/include/asm-x86/cpufeature.h
+++ b/include/asm-x86/cpufeature.h
@@ -186,6 +186,7 @@
#define cpu_has_bts boot_cpu_has(X86_FEATURE_BTS)
#define cpu_has_gbpages boot_cpu_has(X86_FEATURE_GBPAGES)
#define cpu_has_arch_perfmon boot_cpu_has(X86_FEATURE_ARCH_PERFMON)
+#define cpu_has_pat boot_cpu_has(X86_FEATURE_PAT)
#if defined(CONFIG_X86_INVLPG) || defined(CONFIG_X86_64)
# define cpu_has_invlpg 1
diff --git a/include/asm-x86/msr-index.h b/include/asm-x86/msr-index.h
index 3ed9714..af4e07f 100644
--- a/include/asm-x86/msr-index.h
+++ b/include/asm-x86/msr-index.h
@@ -57,6 +57,8 @@
#define MSR_MTRRfix4K_F8000 0x0000026f
#define MSR_MTRRdefType 0x000002ff
+#define MSR_IA32_CR_PAT 0x00000277
+
#define MSR_IA32_DEBUGCTLMSR 0x000001d9
#define MSR_IA32_LASTBRANCHFROMIP 0x000001db
#define MSR_IA32_LASTBRANCHTOIP 0x000001dc
diff --git a/include/asm-x86/mtrr.h b/include/asm-x86/mtrr.h
index 319d065..968794a 100644
--- a/include/asm-x86/mtrr.h
+++ b/include/asm-x86/mtrr.h
@@ -84,6 +84,8 @@
#ifdef __KERNEL__
+extern u8 mtrr_type_lookup(u64 addr, u64 end);
+
/* The following functions are for use by other drivers */
# ifdef CONFIG_MTRR
extern void mtrr_save_fixed_ranges(void *);
diff --git a/include/asm-x86/pat.h b/include/asm-x86/pat.h
new file mode 100644
index 0000000..8b822b5
--- /dev/null
+++ b/include/asm-x86/pat.h
@@ -0,0 +1,16 @@
+
+#ifndef _ASM_PAT_H
+#define _ASM_PAT_H 1
+
+#include <linux/types.h>
+
+extern int pat_wc_enabled;
+
+extern void pat_init(void);
+
+extern int reserve_memtype(u64 start, u64 end,
+ unsigned long req_type, unsigned long *ret_type);
+extern int free_memtype(u64 start, u64 end);
+
+#endif
+
diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index 9cf472a..ca6deb3 100644
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -57,6 +57,12 @@
#define _PAGE_CHG_MASK (PTE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
+#define _PAGE_CACHE_MASK (_PAGE_PCD | _PAGE_PWT)
+#define _PAGE_CACHE_WB (0)
+#define _PAGE_CACHE_WC (_PAGE_PWT)
+#define _PAGE_CACHE_UC_MINUS (_PAGE_PCD)
+#define _PAGE_CACHE_UC (_PAGE_PCD | _PAGE_PWT)
+
#define PAGE_NONE __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_NX)